This chapter, and the volume in which it resides, suggests the need to reconsider the theory of agency capture. Few constructs within the study of American politics and policymaking are more widely discussed than agency capture. However, although scholars, politicians, and the media frequently employ the idea of agency capture, there is neither a clear definition of the construct nor a common way to identify it. In this chapter, I begin to address these shortcomings in three main ways. First, I define agency capture, which I suggest is the control of agency policy decision making by a subpopulation of individuals or organizations external to the agency. Second, I put forward a two-prong test for identifying capture that separates the constructs of “influence” from “control.” I argue that influence is a necessary but not sufficient condition of capture. Third, I provide an empirical assessment of these constructs by applying them to a sample of rules from the U.S. Department of Transportation.

Tasked with filling in the details of congressionally passed statutes, public agencies routinely propose and promulgate legally binding rules and regulations. Although the scope and topics of rules vary dramatically, some of our key public policy battles have been fought and decided via rules. For instance, existing rules specify standards for automobile emissions, clean water, and workplace safety; moreover, forthcoming rules may set requirements for state health exchanges and capital bank standards. In short, rules matter, and so does “rulemaking,” the political and policymaking process by which agency rules are formulated.